Iran is a culturally diverse society, and interethnic relations are generally amicable. The predominant ethnic and cultural group in the country consists of native speakers of Persian. But the people who are generally known as Persians are of mixed ancestry, and the country has important Turkic and Arab elements in addition to the Kurds, Baloch, Bakhtyārī, Lurs, and other smaller minorities (Armenians, Assyrians, Jews, Brahuis, and others). The Persians, Kurds, and speakers of other Indo-European languages in Iran are descendants of the Aryan tribes that began migrating from Central Asia into what is now Iran in the 2nd millennium bc. Those of Turkic ancestry are the progeny of tribes that appeared in the region—also from Central Asia—beginning in the 11th century ad, and the Arab minority settled predominantly in the country’s southwest (in Khūzestān, a region also known as Arabistan) following the Islamic conquests of the 7th century. Like the Persians, many of Iran’s smaller ethnic groups chart their arrival into the region to ancient times.

The Kurds have been both urban and rural (with a significant portion of the latter at times nomadic), and they are concentrated in the western mountains of Iran. This group, which constitutes only a small proportion of Iran’s population, has resisted the Iranian government’s efforts, both before and after the revolution of 1979, to assimilate them into the mainstream of national life and, along with their fellow Kurds in adjacent regions of Iraq and Turkey, has sought either regional autonomy or the outright establishment of an independent Kurdish state in the region.

Also inhabiting the western mountains are seminomadic Lurs, thought to be the descendants of the aboriginal inhabitants of the country. Closely related are the Bakhtyārī tribes, who live in the Zagros Mountains west of Eṣfahān. The Baloch are a smaller minority who inhabit Iranian Baluchistan, which borders on Pakistan.

The largest Turkic group is the Azerbaijanians, a farming and herding people who inhabit two border provinces in the northwestern corner of Iran. Two other Turkic ethnic groups are the Qashqāʾī, in the Shīrāz area to the north of the Persian Gulf, and the Turkmen, of Khorāsān in the northeast.

The Armenians, with a different ethnic heritage, are concentrated in Tehrān, Eṣfahān, and the Azerbaijan region and are engaged primarily in commercial pursuits. A few isolated groups speaking Dravidian dialects are found in the Sīstān region to the southeast.

Semites—Jews, Assyrians, and Arabs—constitute only a small percentage of the population. The Jews trace their heritage in Iran to the Babylonian Exile of the 6th century bc and, like the Armenians, have retained their ethnic, linguistic, and religious identity. Both groups traditionally have clustered in the largest cities. The Assyrians are concentrated in the northwest, and the Arabs live in Khūzestān as well as in the Persian Gulf islands.

Languages

Although Persian (Farsi) is the predominant and official language of Iran, a number of languages and dialects from three language families—Indo-European, Altaic, and Afro-Asiatic—are spoken.

Roughly three-fourths of Iranians speak one of the Indo-European languages. Slightly more than half the population speak a dialect of Persian, an Iranian language of the Indo-Iranian group. Literary Persian, the language’s more refined variant, is understood to some degree by most Iranians. Persian is also the predominant language of literature, journalism, and the sciences. Less than one-tenth of the population speaks Kurdish. The Lurs and Bakhtyārī both speak Lurī, a language distinct from, but closely related to, Persian. Armenian, a single language of the Indo-European family, is spoken only by the Armenian minority.

The Altaic family is represented overwhelmingly by the Turkic languages, which are spoken by roughly one-fourth of the population; most speak Azerbaijanian, a language similar to modern Turkish. The Turkmen language, another Turkic language, is spoken in Iran by only a small number of Turkmen.

Of the Semitic languages—from the Afro-Asiatic family—Arabic is the most widely spoken, but only a small percentage of the population speaks it as a native tongue. The main importance of the Arabic language in Iran is historical and religious. Following the Islamic conquest of Persia, Arabic virtually subsumed Persian as a literary tongue. Since that time Persian has adopted a large number of Arabic words—perhaps one-third or more of its lexicon—and borrowed grammatical constructions from Classical and, in some instances, colloquial Arabic. Under the monarchy, efforts were made to purge Arabic elements from the Persian language, but these met with little success and ceased outright following the revolution. Since that time, the study of Classical Arabic, the language of the Qurʾān, has been emphasized in schools, and Arabic remains the predominant language of learned religious discourse.

Before 1979, English and French, and to a lesser degree German and Russian, were widely used by the educated class. European languages are used less commonly but are still taught at schools and universities.

Religion

The vast majority of Iranians are Muslims of the Ithnā ʿAsharī, or Twelver, Shīʿite branch, which is the official state religion. The Kurds and Turkmen are predominantly Sunni Muslims, but Iran’s Arabs are both Sunni and Shīʿite. Small communities of Christians, Jews, and Zoroastrians are also found throughout the country.

Shīʿism

The two cornerstones of Iranian Shīʿism are the promise of the return of the divinely inspired 12th imam—Muḥammad al-Mahdī al-Ḥujjah, whom Shīʿites believe to be the mahdi—and the veneration of his martyred forebears. The absence of the imam contributed indirectly to the development in modern Iran of a strong Shīʿite clergy whose penchant for status, particularly in the 20th century, led to a proliferation of titles and honorifics unique in the Islamic world. The Shīʿite clergy have been the predominant political and social force in Iran since the 1979 revolution.

Clergy

There is no concept of ordination in Islam. Hence, the role of clergy is played not by a priesthood but by a community of scholars (Arabic ʿulamāʾ). To become a member of the Shīʿite ʿulamāʾ, a male Muslim need only attend a traditional Islamic college, or madrasah. The main course of study in such an institution is Islamic jurisprudence (Arabic fiqh), but a student need not complete his madrasah studies to become a faqīh, or jurist. In Iran such a low-level clergyman is generally referred to by the generic term mullah (Arabic al-mawlā, “lord”; Persian mullā) or ākhūnd or, more recently, rūḥānī (Persian: “spiritual”). To become a mullah, one need merely advance to a level of scholarly competence recognized by other members of the clergy. Mullahs staff the vast majority of local religious posts in Iran.

An aspirant gains the higher status of mujtahid—a scholar competent to practice independent reasoning in legal judgment (Arabic ijtihād)—by first graduating from a recognized madrasah and obtaining the general recognition of his peers and then, most important, by gaining a substantial following among the Shīʿite community. A contender for this status is ordinarily referred to by the honorific hojatoleslām (Arabic ḥujjat al-Islām, “proof of Islam”). Few clergymen are eventually recognized as mujtahids, and some are honoured by the term ayatollah (Arabic āyat Allāh, “sign of God”). The honorific of grand ayatollah (āyat Allāh al-ʿuẓmāʾ) is conferred only upon those Shīʿite mujtahids whose level of insight and expertise in Islamic canon law has risen to the level of one who is worthy of being a marjaʿ-e taqlīd (Arabic marjaʿ al-taqlīd, “model of emulation”), the highest level of excellence in Iranian Shīʿism.

There is no real religious hierarchy or infrastructure within Shīʿism, and scholars often hold independent and varied views on political, social, and religious issues. Hence, these honorifics are not awarded but attained by scholars through general consensus and popular appeal. Shīʿites of every level defer to clergymen on the basis of their reputation for learning and judicial acumen, and the trend has become strong in modern Shīʿism for every believer, in order to avoid sin, to follow the teachings of his or her chosen marjaʿ-e taqlīd. This has increased the power of the ʿulamāʾ in Iran, and it has also enhanced their role as mediators to the divine in a way not seen in Sunni Islam or in earlier Shīʿism.

Sayyids

Those progeny of the family of Muḥammad who are not his direct descendents through the line of the 12th imam are referred to as sayyids. These individuals have traditionally been viewed with a high degree of reverence by believing Iranians and continue to have strong influence in contemporary Iranian culture. Many sayyids are found among the clergy, although in modern Iran they may practice virtually any occupation.

Religious minorities

Christians, Jews, and Zoroastrians are the most significant religious minorities. Christians are the most numerous group of these, Orthodox Armenians constituting the bulk. The Assyrians are Nestorian, Protestant, and Roman Catholic, as are a few converts from other ethnic groups. The Zoroastrians are largely concentrated in Yazd in central Iran, Kermān in the southeast, and Tehrān.

Religious toleration, one of the characteristics of Iran during the Pahlavi monarchy, came to an end with the Islamic revolution in 1979. While Christians, Jews, and Zoroastrians are recognized in the constitution of 1979 as official minorities, the revolutionary atmosphere in Iran was not conducive to equal treatment of non-Muslims. Among these, members of the Bahāʾī faith—a religion founded in Iran—were the victims of the greatest persecution. The Jewish population, which had been significant before 1979, emigrated in great numbers after the revolution.

Settlement patterns

Rural settlement

The topography and the water supply determine the regions fit for human habitation, the lifestyles of the people, and the types of dwellings. The deep gorges and defiles, unnavigable rivers, empty deserts, and impenetrable kavīrs have all contributed to insularity and tribalism among the Iranian peoples, and the population has become concentrated around the periphery of the interior plateau and in the oases. The felt yurts of the Turkmen, the black tents of the Bakhtyārī, and the osier huts of the Baloch are typical, as the tribespeople roam from summer to winter pastures. The vast central and southern plains are dotted with numerous oasis settlements with scattered rudimentary hemispherical or conical huts. Since the mid-20th century the migrations have shortened, and the nomads have settled in more permanent villages.

The villages on the plains follow an ancient rectangular pattern. High mud walls with corner towers form the outer face of the houses, which have flat roofs of mud and straw supported by wooden rafters. A mosque is situated in the open centre of the village and serves also as a school.

Mountain villages are situated on the rocky slopes above the valley floor, surrounded by terraced fields (usually irrigated) in which grain and alfalfa (lucerne) are raised. The houses are square, mud-brick, windowless buildings with flat or domed roofs; a roof hole provides ventilation and light. Houses are usually two stories high, with a stable occupying the ground floor.

Caspian villages are different from those of both the plains and the mountains. The scattered hamlets typically consist of two-storied wooden houses. Separate outbuildings (barns, henhouses, silkworm houses) surround an open courtyard.

Urban settlement

Tehrān, the capital and largest city, is separated from the Caspian Sea by the Elburz Mountains. Eṣfahān, about 250 miles (400 km) south of Tehrān, is the second most important city and is famed for its architecture. There are few cities in central and eastern Iran, where water is scarce, although lines of oases penetrate the desert. Most towns are supplied with water by qanāt, an irrigation system by which an underground mountain water source is tapped and the water channeled down through a series of tunnels, sometimes 50 miles (80 km) in length, to the town level. Towns are, therefore, often located a short distance from the foot of a mountain. The essential feature of a traditional Iranian street is a small canal.

City layout is typical of Islamic communities. The various sectors of society—governmental, residential, and business—are often divided into separate quarters. The business quarter, or bazaar, fronting on a central square, is a maze of narrow arcades lined with small individual shops grouped according to the type of product sold. Modern business centres, however, have grown up outside the bazaars. Dwellings in the traditional style—consisting of domed-roof structures constructed of mud brick or stone—are built around closed courtyards, with a garden and a pool. Public baths are found in all sections of the cities.

Construction of broad avenues and ring roads to accommodate modern traffic has changed the appearance of the large cities. Their basic plan, however, is still that of a labyrinth of narrow, crooked streets and culs-de-sac.

Demographic trends

Iran is a young country: nearly two-fifths of its people are Nearly one-fourth of Iranians are under 15 years of ageor younger. However, the The country’s postrevolutionary boom in births has slowed substantially, and—with a birth rate slightly lower than the world average and a low death rate—Iran’s natural rate of increase is now only marginally higher than the world average. Life expectancy in Iran is some 68 years for men and 71 years for women.

Internal migration from rural areas to cities was a major trend beginning in the 1960s (some three-fifths of Iranians are defined as urban), but the most significant demographic phenomenon following the revolution in 1979 was the out-migration of a large portion of the educated, secularized population to Western countries, particularly to the United States. (Several hundred thousand Iranians had settled in southern California alone by the end of the 20th century.) Likewise, a considerable number of religious minorities, mostly Jews and Bahāʾīs, have left the country—either as emigrants or as asylum seekers—because of unfavourable political conditions. Internally, migration to the cities has continued, and Iran has absorbed large numbers of refugees from neighbouring Afghanistan (mostly Persian [Dari]-speaking Afghans) and Iraq (both Arabs and Kurds).